Meter bearing and seal



June 1954 F. NIESEMANN METER BEARING AND SEAL Filed Sept. 30, 1950 IIIIIIIIH INVENTOR FRITZ Nmsammu I sa /M, WQQW ATTORNEYS bearing and the friction Patented June 15, 1954 2,681,257 METER BEARING AND SEAL Fritz Niesemann,

Rockwell Pa., a corporation of This invention relates United States Patent No. 2,024,059, issued December 10, 1935, to Walter H. Parker et al.

In the usual type of orifice meter, of which that disclosed in the Parker et a1. patent is a typical example, there is a restriction in a conduit connected by a lever to The other end of the scriber shaft is fixed, as by It is a primary object of this invention to provide a new and improved bearing for shafts of meters which prevents leakage of fluid or gas from a chamber containing fluid or gas under pressure to the atmosphere Without unduly inhibiting the rotation of the shaft.

In prior art leakage resistance bearings for rotatable meter shafts, the leakage resistance of the tending to inhibit shaft rotation both varied with the operating temperature resulting in inaccuracies in indication and leakage of the fluid. An important object of this Pittsburgh, Pa.,

Manufacturing Company,

assignor Pittsburgh,

Pennsylvania Application September 30, 1950, Serial No. 187,787 15 Claims. (01. 308-362) A further disadvantage of prior art leakage resistant bearings for meter shafts is that coaxial alignment of the shaft with the bore is quite criti- More specifically, an important object of this invention is to provide a novel bearing structure an internal frusto-conical surface having one edge forming a bearing surface is formed within the housing coaxial center of the scriber shaft and support assembly.

Figure 2 is an enlarged view of the novel hearing structure.

Referring to Figure 1, a scriber shaft I0 is rotatably mounted within and coaxial with. the bore of an elongated tubular, relatively stationary, stainless steel housing 52. The hollow tubular housing I2 is threadedly connected at l3 to a. float chamber casing i l and extends through a hole in that easing into a float chamber |5.. A suitable copper gasket 16 is clamped between opposed shoulders on casing M and housing 12 to prevent leakage of fluid through the threaded connection between them.

The scriber shaft l 0 is rotatably supported Within the hollow the float chamber end of the scriber shaft in which extends through end bearing l8 to the interior of the float chamber 15. Reference is made to said Parker et al. patent for any further details of such float and linkage structure necessary to understand the invention. Scriber arm 26, to which a scribing device such as a pen (not shown) is attached, is mounted on'the opposite end of scriber shaft in by any suitable means such as by block 25. A U-bracket 26, serving at21 as a thrust'bearing for the scriber shaft lll, is rigidly mounted on the exterior of the hollow tubular housing If by any suitable means such as nut 23 threadedly connected as at 29 to the hollow tubular housing l2.

The bore of the hollow tubular housing i2 is considerably greater in diameter than the diameter of the scriber shaft id throughout the major portion of its length, but at the scriber arm end 39 the bore is reduced in diameter until it is only slightly larger than that of the scriber shaft ill. The body of plastic packing material 2!] surrounds scriber shaft iii and is longitudinally positioned thereon between end 39 of housing i2 and a sleeve member 34, which is mounted for free longitudinal movement within the tubular housing i2. Scriber shaft iii extends through the relatively large bore of sleeve member 3i, being supported by bearing i8 and body 2%; as previously stated.

As is best shown in Figure 2, the body of lastic material 29 is toroidal in shape, having an external cylindrical surface 32 and oppositely inclined conical external end surfaces 233 and iii A suitable apex has been found to be approximately 90". The diameter of the cylindrical surface 32 is sufficiently smaller than that of the bore of housing IE to allow for radial expansion of the plastic body throughout the operating temperature range without surface contact between cylindrical surface 32 and the bore of housing A clearance of .0125 inch has been found to be satisfactory for the presently contemplated temperature range and for the particular plastic used.

Truncated annular conical surfaces as and 36 are formed within the scriber arm end (it of housing If and within the adjacent end of sleeve M respectively. These conical surfaces are preferably equally and oppositely inclined and have apex angles larger than those of conical surfaces 33 and 3d, apex angles of 118 having been found to be suitable. Plastic body 2b which is a toroidal bearing element contacts housing l2 along the circular intersection of conical surface 35 and the cylindrical bore 31 which is coaxial with the main bore of the housing 12, and contacts sleeve 3! along the circular intersection of the core of sleeve 3| with the conical surface 36 thereof. By this construction, the area of contact between body and stationary housing If and sleeve 3i is reduced to a minimum, there being substantially line contact between body 29 and sleeve 3-! and housing 12.

A coil type compression spring 38 is mounted in compressed condition within the bore of the tubular housing l2 with one end abutting against a stop, which as disclosed is the end as of bearing 18, and its other end abutting against the inner end M! of sleeve member 3!. The body of plastic packing material 28 is thus maintained under constant pressure between the bearing edges of the two conical surfaces and 3d.

The conical surfaces 33 and as of body 2c in cooperation with the mating conical'suriace's angle for these conical surfaces plied pressure tends to 35 and 36 on the bore of housing l2 and on the end of sleeve 3| form a self-centering bearing for the shaft II]. There is no appreciable increase in bearing pressure as the plastic body 20 expands with an increase in temperature because clearance has been provided to permit radial expansion of body 20 without contacting the bore of housing i2, because sleeve 31 is movable within the bore to permit longitudinal expansion of body 29, and because the conical surfaces 33 and 34 can shift relative to the edges of surfaces 35 and 36 to permit radial expansion of the conical ends of body 20. It will be noted that in this improved bearing structure, the leakage resistance and the friction of the bearing will remain constant throughout the temperature range. This apwedge plastic body 20 firmly against the shaft H! to form a tight seal and to form a leakage resistant bearing for shaft ill between plastic body 25 and housing l2. It should be noted that in this construction neither the friction at the bearing nor the leak-. age resistance of the bearing will be changed substantially if the axis of the shaft should not be exactly coaxial with that of the bore of housing 12. If the shaft It should be slightly bentfor example, the axes of conical surfaces 33 and 34 will be shifted slightly relative to the axes-of conical surfaces 35. and 36 respectively, but plastic body 20 being slightly deformable under pressure, surfaces 33 and 36 will be conformed at their respective lines of contact with surfaces 35 and 35 to the circular bearing areas thereof. In this manner the leakage resistance of the seal between plastic body 20 and housing IE will not be decreased and the friction at the bearing will not be increased substantially. The outside of the end of sleeve 3| adjacent surface 36 is reduced to provide an annular recess 41 between the sleeve 3i and the housing bore to aid the self aligning action of plastic body 2% relative thereto.

From the foregoing description it is seen that the plastic packing material body 28 for the scriber shaft according to the invention must be chemically inert to the metals with which it comes into contact, and to the fluids, the flow of which is being measured. It must be hard but capable of being deformed slightly at operating temperature and under pressure to con form by cold flow to the bearing surfaces without substantial radial expansion due to that pressure. The packing material should be nonwater absorbent, and should have a minimum coefficient of friction even when subjected to considerable bearing surface pressure, and without lubrication. Of the solid, pressure deformable plastics available the ethylene polymers have been found to meet these requirements very well, and the tetrafluoro ethylene polymers have been found exceptionally suitable for this purpose. The tetrafluoro ethylene polymers have the following chemical analysis:

i i if i if r rt rrrrr F F F F F F F i the shaft and to motion of t efioat even if the shaft is slightly bent. No lubrication is necessary and the body of solid synthetic plastic conforms the contacted portions of surfaces 35 and 36 that there is no fluid leakage either between shaft and body or between body 20 and edge of surface even if slightly bent.

Since the invention may be embodied in other specific forms or applied to meters other than the foregoing description, and all changes which come within the meamng and range of equiva- What is claimed and desired to be secured by United States Letters Patent is:

said body being a hard, solid plastic body formed of an ethylene polymer which may undergo bore for pressing said body form a leakage resistant self-centering bearing for said shaft.

2. In the meter defined in claim 1, the material of said hard, solid plastic ethylene polymer body being a tetrafiuoro ethylene polymer.

sponsive element and the indicating means, a hollow housing secured at one end with said opening by a fluid tight connection, said shaft through the bore of the hollow housing and being mounted for rotation therein, and means within said hollow housing for preventing leakage of fluid from said along said shaft, said leakage pressure chamber preventing means the shaft is for urging the body comprising a toroidally shaped body having its outer diameter sufiiciently smaller than the diameter of said housing bore to permit expansion of said body throughout the operating temperature range thereof without contacting said bore, said body being a solid plastic body that may undergo slight deformation under pressure, means within said housing bore defining a fixed annular edge, and means acting substantially coaxially with said fixed annular edge and with said shaft to provide a low friction leakage resistance bearing for said shaft.

gaging said body, and a compression spring surrounding said shaft extending between said other abutment and said sleeve.

defined in claim 5, said shoulder comprising an internal frusto-conical surface having a predetermined apex angle and the adjacent end of said plastic body having an external frusto-conical sulrface angle smaller than said predetermined apex a substantially frusto-conical end face in annular line contact with said body, and an axially acting compression spring in said bore whereby substantially annular line contact is established between said sleeve and said body.

8. In the meter defined in claim 5, said means against said shoulder. comprising a sleeve slidable longitudinally in said bore and having an annular face substantially aperture formed through a wall thereof, a

I 1y conformable under centered between the shaft and bore resiliently urged into annular line contact with said body.

mounted for translatory movement axially of said shaft, a toroidal "plastic surrounding, journalling and conformedin body formed of an anti-friction fluid tight relation to said shaft between said abutments, and means for resiliently biasing said movable abutment, toroidal body, and fixed abutjment into fluid tight contact along said annular edges.

10. In a meter, a sealed housing having an able shaft projecting outwardly from said housing through said aperture, a self-centering bearing for said shaft comprising a pair of abutments within said housing around said shaft each being apertured substantially coaxial with said shaft, the opposed faces of said abutments being concave in form and terminating inwardly in annular edges, a toroidal body formed of a hard plastic slightly deformable underpressure, said body surrounding, journalling and being conformed in fluid tight relation with said shaft between said abutments, one of said abutments being fixed in fluid tight relation with said housing and the other resiliently biased toward said fixed abutment against said said toroidal body being'of such convex form as to contact said abutments only along said inner annular edges whereby line contact is established therebetween and fluid leakage through said bearing is prevented.

11. In a meter, a aperture formed through a wall thereof, a rotatable shaft projecting from said housing, a selfcentering prising a pair of abutments within said housing around said shaft having apertures substantially coaxial with said shaft, the opposed faces of said abutments being concave in form and terminating inwardly in annular edges surrounding and spaced from said shaft, a toroidal body surrounding, J'Ournalling, and conformed in fluid .tight relation to said shaft between said abutments, one

of said abutments being fixed in fluid tight relation with said housing and the other resiliently biased toward said fixed abutment against-said toroidal body, the end faces of said toroidal body being of such form as to contact said abutments along said edges only and said toroidal body being formed of a hard lowfriction plastic slightpressure to the contacted portions of said abutments and to said shaft to form a fluid tight bearing for said shaft.

12. In a meter, a sealed housing formed with an aperture through a wall thereof, a shaft projecting outwardly from said housing through said aperture, an abutment surrounding said shaft inwardly of said aperture and formed with an annular edge, a toroidal body formed of an ethylene polymer subjectto slight cold flow under pressure, said body being disposed on said shaft in fluid tight relation therewith inwardly of said edge and having a convex surface adjacent said edge, and means resiliently biasingsaid toroidal rotattoroidal body, the end faces of sealed housing having an fluid tight bearing for said shaft com-,

' diameter of said bore body toward said abutment so that the convex surface thereof contacts said abutment along said edge only and providing a fluid tight low friction bearing for said shaft.

13. In a meter, a sealed housing formed with a longitudinal bore terminating in an end aperture; a shaft projecting outwardly from said housing through said bore and aperture; an abutment surrounding said shaft within said bore inwardly of said aperture and formed with an inner annular edge; a toroidal body having an outside diameter. suificiently smaller than the diameter oi bore to permit expansion thereof over its normal operating range without contacting the wall of said bore and substantially larger than that of said edge, said toroidal body being formed of an ethylene polymer, subject to slight cold flow under pressure, being mounted on said shaft in fluid tight relation therewith inwardly of said edge and having a convex face adjacent said. edge; and means resiliently biasing said toroidal body toward said abutment so that the convex surface thereof contacts said abutment along said edge only.

14. In a meter, a sealed housing formed with an aperture through a wall thereof, a shaft projecting outwardly from said housing through said aperture, an abutment surrounding said shaft inwardly of said aperture and formed with an annular edge, a toroidal body of a tetrafiuoro ethylene polymer subject to slight cold flow under pressure, said body being. disposed in surrounding fiuid tight relation to said shaft inwardly of said edge and having a convex surface adjacent said edge, and means resiliently biasing said toroidal body toward said abutment so that the convex surface thereof contacts said abutment along said edge only thereby providing a fluid tight low friction bearing for said shaft.

15. In a meter, a sealed housing formed with a longitudinal bore terminating in an end aperture; a shaft projecting outwardly from said housing through said bore and aperture; an abutment surrounding said shaft within said bore inwardly of said aperture and formed with an inner annular edge; a toroidal body having an outside, diameter sufficiently smaller than the to permit expansion thereof over its normal operating range without contacting the wall of said bore and substantially larger than that of said edge, said toroidal body being formed of a tetrafiuoroethylene polymer abutment so that the convex surface thereof contacts said abutment along said edge only.

References Cited in the file of this patent UNITED STATES PATENTS Number Name 7 Date 275,193 Grannan Apr. 3, 1883 412,874 Chaddaclr Oct. 15, 1889 1,494,169 Johnson May 13, 1924 1,923,291 Zimmerer Aug. 22, 1933 1,997,069 More et al Apr, 9, 1935 2,024,059 Parker et al Dec. 10,, 1935 2,129,069 Roberts Sept. 6, 1938 2,199,880 Elliott May '7, 1940 2,260,820 Barr Oct. 28,, 1941 2,467,312 Jack Apr. 12, 1949 

